Fast Arctic Warming

The Economist warned in April 2017 that the economic gains from oil extraction and sea routes in the Arctic would be heavily outweighed by economic setbacks resulting from metling sea and land ice and permafrost. “The Paris agreement will not save the Arctic as it is today,” says Lars-Otto Reiersen, executive secretary of the group behind the latest edition of “Snow, Water, Ice, Permafrost in the Arctic” (SWIPA), a report produced under the auspices of the Arctic Council, a scientific-policy club for the eight countries with territory in the Arctic Circle) …The thaw is happening far faster than once expected. Over the past three decades the area of sea ice in the Arctic has fallen by more than half and its volume has plummeted by three-quarters (see map). SWIPA estimates that the Arctic will be free of sea ice in the summer by 2040. Scientists previously suggested this would not occur until 2070. The thickness of ice in the central Arctic ocean declined by 65% between 1975 and 2012; record lows in the maximum extent of Arctic sea ice occurred in March.

Atmospheric concentration of carbon dioxide has now reached 400 parts per million (ppm), up from 280ppm three centuries ago; the Earth is on average 1ºC hotter than in pre-industrial times. Although 190-odd countries signed up to limit warming to “well below” 2ºC above pre-industrial temperatures in Paris in 2015, pledges for mitigating action are likely to see temperatures increase by around 3ºC—assuming countries stick to their promises. But different parts of the world warm at different rates. Even if the Paris agreement is implemented in full, the Arctic will warm by between 5ºC and 9ºC above the 1986-2005 average over the Arctic ocean in winter.